COL4A4 and chronic kidney disease: In a report of 53 patients with heterozygous COL4A3/COL4A4 mutations in 25 families, microhematuria, proteinuria (>0.2 g/g⋅Cr), CKD, and ESKD were observed in 100%, 17%, 7.5%, and 5.7% of subjects, respectively [31].